Methods Of Forming A Plurality Of Conductive Lines In The Fabrication Of Integrated Circuitry, Methods Of Forming An Array Of Conductive Lines, And Integrated Circuitry

ABSTRACT

A method of forming a pair of conductive lines in the fabrication of integrated circuitry includes forming a trench into a damascene material received over a substrate. Conductive material is deposited over the damascene material and to within the trench to overfill the trench. The conductive material is removed back at least to the damascene material to leave at least some of the conductive material remaining in the trench. Etching is conducted longitudinally through the conductive material within the trench to form first and second conductive lines within the trench which are mirror images of one another in lateral cross section along at least a majority of length of the first and second conductive lines. Other implementations are contemplated.

TECHNICAL FIELD

Embodiments disclosed herein pertain to methods of forming a pluralityof conductive lines in the fabrication of integrated circuitry, tomethods of forming an array of conductive lines, and to integratedcircuitry independent of method of fabrication.

BACKGROUND

Integrated circuits are typically formed on a semiconductor substratesuch as a silicon wafer or other semiconducting material. In general,layers of various materials which are either semiconducting, conductingor insulating are utilized to form the integrated circuits. By way ofexample, the various materials are doped, ion implanted, deposited,etched, grown, etc. using various processes. A continuing goal insemiconductor processing is to continue to strive to reduce the size ofindividual electronic components thereby enabling smaller and denserintegrated circuitry.

One technique for patterning and processing semiconductor substrates isphotolithography. Such includes deposition of a patternable maskinglayer commonly known as photoresist. Such materials can be processed tomodify their solubility in certain solvents, and are thereby readilyusable to form patterns on a substrate. For example, portions of aphotoresist layer can be exposed to actinic energy through openings in aradiation-patterning tool, such as a mask or reticle, to change thesolvent solubility of the exposed regions versus the unexposed regionscompared to the solubility in the as-deposited state. Thereafter, theexposed or unexposed regions can be removed, depending on the type ofphotoresist, thereby leaving a masking pattern of the photoresist on thesubstrate. Adjacent areas of the underlying substrate next to the maskedportions can be processed, for example by etching or ion implanting, toeffect the desired processing of the substrate adjacent the maskingmaterial. In certain instances, multiple different layers of photoresistand/or a combination of photoresists with non-radiation sensitivemasking materials are utilized.

The continual reduction in feature sizes places ever greater demands onthe techniques used to form the features. For example, photolithographyis commonly used to form patterned features, such as conductive lines. Aconcept commonly referred to as “pitch” can be used to describe thesizes of the features in conjunction with spaces immediately adjacentthereto. Pitch may be defined as the distance between an identical pointin two neighboring features of a repeating pattern in a straight linecross section, thereby including the maximum width of the feature andthe space to the next immediately adjacent feature. However, due tofactors such as optics and light or radiation wave length,photolithography techniques tend to have a minimum pitch below which aparticular photolithographic technique cannot reliably form features.Thus, minimum pitch of a photolithographic technique is an obstacle tocontinued feature size reduction using photolithography.

Pitch doubling or pitch multiplication is one proposed method forextending the capabilities of photolithographic techniques beyond theirminimum pitch. Such typically forms features narrower than minimumphotolithography resolution by depositing spacer-forming layers to havea lateral thickness which is less than that of the minimum capablephotolithographic feature size. The spacer-forming layers are commonlyanisotropically etched to form sub-lithographic features, and then thefeatures which were formed at the minimum photolithographic feature sizeare etched from the substrate. Using such technique where pitch isactually halved, such reduction in pitch is conventionally referred toas pitch “doubling”. More generally, “pitch multiplication” encompassesincrease in pitch of two or more times and also of fractional valuesother than integers. Thus, conventionally, “multiplication” of pitch bya certain factor actually involves reducing the pitch by that factor.

Conductive lines may be used in integrated circuitry as electricalinterconnects and as bit lines in memory circuitry. Metals, whetherelemental metals, alloys of different elemental metals, or conductivemetal compounds, are dominant interconnect material due to their highelectrical conductivity. One manner of forming conductive lines useswhat is referred to as damascene processing. In such, a suitable moldingmaterial is formed over a substrate over which the conductive lines areto be formed. Trenches are etched into the molding material into desiredshapes and orientations of the conductive lines being formed. Thetrenches are at least partially filled with conductive material informing conductive lines within the trenches.

It is difficult to fill very narrow trenches in damascene formation ofconductive lines, particularly as the width of such lines has fallen to20 nanometers and below using pitch multiplication techniques because ofresistivity requirements. Effective resistivity of the trench fillmaterial increases at these dimensions. Additionally, voids may formwithin the conductive material within the trenches due to the materialnot spanning completely across the trench width. Voids inherently reducethe volume of conductive material in the line. Such has not beenparticularly problematic at trench/line widths of at least 60nanometers.

While the invention was motivated in addressing the above-identifiedissues, the invention is no way so limited.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic top plan view of a substrate in process inaccordance with an embodiment of the invention.

FIG. 2 is a cross section taken through line 2-2 in FIG. 1.

FIG. 3 is a view of the FIG. 2 substrate at a processing step subsequentto that shown by FIGS. 1 and 2.

FIG. 4 is a top plan view of the FIG. 1 substrate at a processing stepsubsequent to that shown by FIG. 3.

FIG. 5 is a cross section taken through line 5-5 in FIG. 4.

FIG. 6 is a view of the FIG. 5 substrate at a processing step subsequentto that shown by FIGS. 4 and 5.

FIG. 7 is a top plan view of the FIG. 4 substrate at a processing stepsubsequent to that shown by FIG. 6.

FIG. 8 is a cross section taken through line 8-8 in FIG. 7.

FIG. 9 is a view of the FIG. 8 substrate at a processing step subsequentto that shown by FIGS. 7 and 8.

FIG. 10 is a view of the FIG. 9 substrate at a processing stepsubsequent to that shown by FIG. 9.

FIG. 11 is a top plan view of the FIG. 7 substrate at a processing stepsubsequent to that shown by FIG. 10.

FIG. 12 is a cross section taken through line 12-12 in FIG. 11.

FIG. 13 is a top plan view of the FIG. 11 substrate at a processing stepsubsequent to that shown by FIGS. 11 and 12.

FIG. 14 is a cross section taken through line 14-14 in FIG. 13.

FIG. 15 is a view of the FIG. 14 substrate at a processing stepsubsequent to that shown by FIGS. 13 and 14.

FIG. 16 is a top plan view of the FIG. 13 substrate at a processing stepsubsequent to that shown by FIG. 15.

FIG. 17 is a view of the FIG. 16 substrate at a processing stepsubsequent to that shown by FIG. 16.

FIG. 18 is a diagrammatic sectional view of a substrate in process inaccordance with an embodiment of the invention.

FIG. 19 is a view of the FIG. 18 substrate at a processing stepsubsequent to that shown by FIG. 18.

FIG. 20 is a top plan view of the FIG. 19 substrate at a processing stepsubsequent to that shown by FIG. 19.

FIG. 21 is a cross section taken through line 21-21 in FIG. 20.

FIG. 22 is a top plan view of the FIG. 20 substrate at a processing stepsubsequent to that shown by FIGS. 20 and 21.

FIG. 23 is a cross section taken through line 23-23 in FIG. 22.

FIG. 24 is a top plan view of the FIG. 22 substrate at a processing stepsubsequent to that shown by FIGS. 22 and 23.

FIG. 25 is a cross section taken through line 25-25 in FIG. 24.

FIG. 26 is a top plan view of the FIG. 24 substrate at a processing stepsubsequent to that shown by FIGS. 24 and 25.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

Example embodiment methods of forming a plurality of conductive lines inthe fabrication of integrated circuitry are described with reference toFIGS. 1-17. Referring to FIGS. 1 and 2, a substrate fragment, forexample a semiconductor substrate, is indicated generally with referencenumeral 10. In the context of this document, the term “semiconductorsubstrate” or “semiconductive substrate” is defined to mean anyconstruction comprising semiconductive material, including, but notlimited to, bulk semiconductive materials such as a semiconductive wafer(either alone or in assemblies comprising other materials thereon), andsemiconductive material layers (either alone or in assemblies comprisingother materials). The term “substrate” refers to any supportingstructure, including, but not limited to, the semiconductive substratesdescribed above.

Substrate 10 includes a bulk semiconductor substrate 12, for examplemonocrystalline silicon. Trench isolation 16 (i.e., one or both ofsilicon dioxide and silicon nitride) has been formed within bulksubstrate 12 to define lines, rows, or columns of active area 14 ofmaterial 12. Semiconductor-on-insulator processing might alternately oradditionally be employed, and whether existing or yet-to-be developed.Lines of active area 14 might be equal or different in width, andregardless might be equally spaced from immediately adjacent lines ofactive area. An example transistor gate construction 17 has been formedorthogonally relative to the longitudinal orientation of active areas14. Such may comprise a field effect transistor gate construction andmay or may not include charge storage regions, for example, in thefabrication of a programmable erasable transistor gates having floatinggate regions.

Referring to FIG. 3, insulative material 18 has been formed overunderlying substrate material. Such may be homogenous or non-homogenous,with doped or undoped silicon dioxide and silicon nitride beingexamples.

Referring to FIGS. 4 and 5, an array of contact openings has been formedthrough insulative layer 18 to regions of active area 14. Such have beenfilled with conductive material 20. By way of example, such might beformed by photolithography and anisotropic etch, followed by depositionof conductive material 20, and followed by planarization back ofconductive material 20 at least to an outermost surface of insulativematerial 18. Conductive material 20 may be homogenous or non-homogenous,with conductively doped polysilicon, elemental metals, alloys ofelemental metals, and conductive metal compounds being examples.Elemental tungsten with or without one or more conductive barrier layersare examples. FIGS. 4 and 5 show but one example substrate over which aplurality of conductive lines may be fabricated in accordance withexample embodiments of the invention. Any other substrate, whetherexisting or yet-to-be developed, may be used.

Referring to FIG. 6, a damascene material has been deposited as part ofsubstrate 10. In the context of this document, a “damascene material” isany material whether existing or yet-to-be developed which is used tomake conductive interconnect lines in damascene-like manners. Suchencompass forming trenches partially or fully through the damascenematerial in the shape of desired circuitry conductive interconnectinglines. Conductive material is subsequently deposited into the linetrenches, followed by optional removal of excess conductive material andof some or all of the damascene material. Subtractive patterning ofconductive material received outwardly of the damascene material mightalternately or additionally occur.

Damascene material 24 may be any of insulative, semiconductive, orconductive, including any combinations thereof. Example insulativecompositions for damascene material 24 include silicon dioxide andsilicon nitride, and whether doped or undoped. Example semiconductivematerials include semiconductively doped monocrystalline silicon andpolycrystalline silicon. Example conductive materials includeconductively doped semiconductive materials, conductive elementalmetals, conductive metal compounds, and alloys of conductive elementalmetals. Damascene material 24 may be of any suitable thickness, withfrom 100 Angstroms to 1 micron being an example range. Such may or maynot have a planar outermost surface, and such may or may not in whole orin part remain as part of the finished integrated circuitryconstruction. In one ideal embodiment, such is insulative and largelyremains as part of the finished integrated circuitry construction, aswill be apparent from the continuing discussion.

Referring to FIGS. 7 and 8, at least one trench 25 has been formed intodamascene material 24. FIGS. 7 and 8 show a plurality of trenches 25having been formed, and which are oriented parallel one another andlargely of common overall shape. However in some embodiments, only asingle trench may be fabricated, and if more than one trench isfabricated, each need not be of common shape nor spacing relative to oneanother. Trenches 25 may be formed by any existing or yet-to-bedeveloped techniques, with photolithography and subsequent subtractiveetching being an example. In one embodiment and as shown, trenches 25extend completely though damascene material 24.

An example trench 25 may be considered as having first and secondopposing trench sidewalls 28 and 30. First trench sidewall 28 islongitudinally elongated to comprise a longitudinal contour of a firstsidewall of one of a plurality of conductive lines being formed, as willbecome apparent in the continuing discussion. Likewise, second trenchsidewall 30 is longitudinally elongated to comprise a longitudinalcontour of a first sidewall of another of the plurality of conductivelines being formed, as also will be apparent in the continuingdiscussion.

Reference to “first” and “second” herein is for ease and clarity indescription, with such references of course being reversible. Forexample, first trench sidewall 28 is shown as being the left sidewall inthe figures, while second sidewall 30 is represented as being the rightsidewall in the figures. Such might of course be reversed. Regardless,such trench sidewalls will be used at least in part to definelongitudinal contours of different conductive lines which are spacedrelative to one another at least in the depicted FIG. 8 cross section.

Two or more conductive lines may be fabricated relative to each trench.In one embodiment, only two conductive lines are formed with respect toeach trench. Regardless, in one embodiment, trenches 25 may beconsidered as having a minimum width 32 between sidewalls 28 and 30which is at least about 3 W_(m), where W_(m) is the minimum width of theconductive lines being formed with respect to each trench. In thecontext of this document, use of “about” requires plus or minus 10percent of the stated dimension. In one embodiment, trench minimum width32 is equal to about 3 W_(m), and in one embodiment equal to 3 W_(m).

The integrated circuitry being formed may be fabricated with or withoutphotolithography. Further, if using photolithography, W_(m) may be at aminimum photolithographic feature size F with which the integratedcircuitry is fabricated, or may be less than F. For example, existing oryet-to-be developed pitch multiplication techniques may be used infabrication of some or all of the features.

Regardless, FIGS. 7 and 8 show an example embodiment wherein individualtrenches 25 overlie two active areas 14 and the dielectric materialspace received there-between. Further, trenches 25 overlie two differentconductive contacts 20 to the respective underlying active areas. Thewidths of active areas 14 and the space there-between may or may not befabricated at the minimum feature size, and may or may not be equal.Regardless, other embodiment trenches 25 may be used. Embodiments of theinvention are believed to have greatest applicability where individualconductive lines being fabricated have minimum widths of 20 nanometersand below. Further and regardless, trenches 25 might be modified aftertheir initial fabrication, for example by etch of and/or deposition overtheir respective sidewalls.

Referring to FIG. 9, conductive material has been deposited to withinthe trenches to span between the respective first and second sidewalls.Such conductive material may be homogenous or non-homogenous, and maycomprise different composition layers. In FIG. 9, the conductivematerial comprises a conductive liner 34 comprising a first compositionand a conductive fill material 35 comprising a second composition whichis received over conductive liner 34. Each material 34 and 35 may behomogenous or non-homogenous, and may comprise different compositionlayers. In one embodiment, some attributes of the stated first andsecond compositions are different relative to one another physicallyand/or chemically. An example first composition is one or both oftitanium and titanium nitride which may facilitate adhesion of theconductive lines being formed to underlying insulative material 18 wheresuch comprises silicon dioxide. Regardless, example fill materials 35include aluminum, ruthenium, palladium, tungsten, copper, titanium andmetal silicides.

FIG. 9 shows conductive material 34/35 having been deposited to overfilltrenches 25. Alternate techniques may of course be used, for example aselective deposition within trenches 25 using electrochemical or otherexisting or yet-to-be developed processing which may or may not fullyfill or over fill trenches 25. Regardless, FIG. 10 shows removal ofconductive material 34/35 back at least to damascene material 24.Multiple conductive lines will be fabricated from conductive material34/35 within each trench, with the discussion proceeding with respect tofabrication of a pair of conductive lines within each trench 25. In oneembodiment, conductive material 34/35 comprises a first sidewall 36 ofeach of a pair of conductive lines being formed with respect to eachtrench 25.

Herein lies one possible advantage of certain embodiments of theinvention which may be achieved in overcoming some of the issuesindentified in the Background section with respect to existing prior artchallenges. Specifically, in existing damascene processing, asindividual minimum conductive line width has reached 20 nanometers andbelow, it is difficult to completely fill such narrow width damascenetrenches completely with conductive material. Where multiple 20nanometer or sub-20 nanometer lines are formed relative to a damascenetrench in accordance with the continuing discussion, complete spanningof the conductive material between trench sidewalls which are more than20 nanometers apart may more readily occur regardless of depositionmethod of the conductive material.

Referring to FIGS. 11 and 12, masking material 40 has been deposited andpatterned relative to underlying substrate material. Where lithographyis used, such may or may not be patterned to be at, above, or belowminimum lithographic feature size with which the integrated circuitry isfabricated. Examples for material 40 include photoresist (includingmulti-layer resist with or without hard masking material), amorphouscarbon, and transparent carbon.

Referring to FIGS. 13 and 14, spacers 42 have been formed on lateralsidewalls of masking material 40. Such may be formed, for example bydeposition of a material over masking material 40 to a thickness of adesired maximum width of spacers 42 followed by anisotropic etching ofsuch material. Alternately, spacers 42 may be grown largely selectivelyrelative to sidewalls of masking material 40. For example where maskingmaterial 40 comprises transparent carbon, example plasma depositionchemistries for growing spacers 42 are fluorocarbons,hydrofluorocarbons, chlorofluorocarbons, halocarbons orhydrohalocarbons. Specific examples include CHF₃, CH₂F₂, C₂F₆, C₂HF₅,and C₃F₈. The flow rate may depend on which feed gas is used, and can bedetermined by one of skill in the art. Generally, flow rates would be inthe range of 25-200 sccm, although flow rates outside this range mayalso be used. As a specific example in a plasma deposition tool, source(top) power may be from 1000 to 3500 Watts, bias (bottom) power at from0 to 400 Watts, chamber pressure from 2 to 5 mTorr, and gas flow ratefrom 10 sccm to 50 sccm. Such will tend to deposit greater thickness ofmaterial 42 over sidewalls as opposed to over top surfaces.

Regardless, FIGS. 13 and 14 show an example embodiment wherein maskingblocks 45 have been formed, and which comprise material 40 and spacermaterial 42. Openings 47 are received between masking blocks 45.Individual of masking blocks 45 span between and partially maskrespective immediately adjacent of two trenches 25. Masking blocks 45may be fabricated in other manners and be of other shape(s).

Referring to FIGS. 15 and 16, conductive material 34/35 has been etchedthrough longitudinally between first trench sidewall 28 and secondtrench sidewall 30 (FIG. 16.). In one embodiment and as shown, such hasbeen conducted through openings 47 between masking blocks 45. FIGS. 15and 16 show such etching as forming a first conductive line 52 and asecond conductive line 56 with respect to each trench 25. Such alsoforms a longitudinal contour of a second sidewall 58 of each of firstand second conductive lines 52 and 56 within each trench 25. In oneembodiment, the longitudinal etching has formed conductive lines 52 and56 to be mirror images of one another, for example as shown in FIG. 16.

FIGS. 15 and 16 show one embodiment wherein the etching of theconductive material was centered between the sidewalls of trench 25.Such also show first conductive lines 52 and second conductive lines 56within a respective trench 25 as being of the same shape in lateralcross section along at least a majority of length of conductive lines 52and 56. Further, FIGS. 15 and 16 show an example embodiment wherein theetching of conductive material 34/35 forms first and second conductivelines 52, 56 to be mirror images of one another in lateral cross sectionalong at least a majority of length of the first and second conductivelines. In one embodiment and as shown, the etching of conductivematerial 34/35 forms each of the first and second conductive lines tohave first sidewall 36 to be of the first composition of layer 34 andalso to comprise a base layer of each line 52, 56 of the firstcomposition of layer 34. Further, the etching of the conductive materialhas formed that portion of second sidewall 58 which is received abovebase layer 34 of each of the first and second conductive lines to be ofthe second composition of material 35.

FIGS. 15 and 16 show an example embodiment wherein conductive lines 52and 56 have a minimum width W_(m) (FIG. 16). In one embodiment, W_(m) isno greater than 20 nanometers, for example wherein the minimum spacebetween the longitudinal contours within each of the conductive linesdefined by sidewalls 36 and 58 is no greater than 20 nanometers.Regardless, in some embodiments, minimum lateral width of first andsecond conductive lines 52, 56 may be further reduced or increased byetching or conductive material addition, respectively. FIGS. 15 and 16also show an embodiment wherein the etching of the conductive materialforms a space 64 within trenches 25 between the respective first andsecond conductive lines 52, 56. In one embodiment, minimum width ofspace 64 may be equal to about W_(m) in lateral cross section.Alternately, the minimum width of space 64 may be less than or greaterthan W_(m).

In one embodiment, first and second conductive lines 52, 56 may beconsidered as comprising a pitch P (FIG. 15), and wherein the minimumwidth 32 (FIGS. 7 and 8) of trenches 25 is equal to about 1.5 P asshown, and in one embodiment regardless of whether trench minimum width32 is about 3 W_(m).

Example first and second conductive lines 52, 56 may be fabricated tocomprise bit lines in DRAM and/or flash memory circuitry. Lines 52. 56may additionally or alternately be used in other circuitry, such aslogic circuitry.

Referring to FIG. 17, dielectric material 70 has been deposited overunderlying substrate and to fill spaces 64 with a dielectric material.Dielectric material 70 may be homogenous or non-homogenous, and maycomprise different composition layers. FIG. 17 shows one idealembodiment wherein material 70 has been deposited to comprise a singularvoid 72 received between example mirror image pairs of conductive lines52/56. Provision of voids 72 as shown may provide effective decreaseddielectric constant k, and thereby reduced parasitic capacitance betweenadjacent conductive lines 52 and 56. In some embodiments, a singularvoid 52 may be formed, and in other embodiments multiple voids may beformed. Regardless, voids 72 may be formed during the act of depositingdielectric material 70, although such may be formed thereafter.

For example, void formation may result in a plasma enhanced chemicaldeposition process of a silicon dioxide material usingtetraethylorthosilicate (TEOS), and O₂ as deposition precursors. Voidformation can be promoted in such a deposition by maximizing depositionrate, maximizing precursor flow rates, using single frequencyprocessors, maximizing temperature, and reducing pressure. Voids can bepromoted by intentionally degrading the step coverage of the depositionprocess. Typically, this can be done by running the process in masstransfer controlled regime in which reactant flux reaching the surfaceof the structure controls deposition rate. By creating a flux gradientfrom top to bottom, faster growth on top of an opening will be achievedand effectively forms a singular void when pinched off. Voids 72 may ormay not be equally spaced laterally between the immediately adjacentconductive lines 52 and 56. Regardless, FIG. 17 shows idealplanarization of dielectric material 70.

Damascene material 24 may be removed in whole or in part after formationof lines 52 and 56, and before depositing material 70. Alternately, noneof damascene material may be removed after formation of lines 52 and 56.

Another embodiment is described with reference to FIGS. 18-26 withrespect to a substrate fragment 10 a. Like numerals from thefirst-described embodiment have been utilized where appropriate, withsome construction differences being indicated with the suffix “a” orwith different numerals. In FIG. 18, damascene material 24 a is shown tobe slightly thicker than that of the first-described embodiment wherein,for example, first and second conductive lines will be formed withrespect to each trench 25 a which are about of the same thickness asthat in the first-described embodiment. Trenches 25 a accordingly areshown to include greater volume of material 34 a and 35 a then in thefirst-described embodiment. For purposes of the continuing discussionwith respect to this embodiment, trenches 25 a have first and secondopposing trench sidewalls 28 a and 30 a which span an elevation E ofdamascene material 24 a.

Referring to FIG. 19, conductive material 34 a/35 a has been recessedwithin trenches 25 a. A first trench-wall 82 and a second trench-wall 84are formed over recessed conductive material 34 a/35 a, and whereinfirst trench-wall 82 and second trench-wall 84 are received withinelevation E of damascene material 24 a. In one embodiment and as shown,first trench-wall 82 is formed to comprise an upper portion of firsttrench sidewall 28 a and second trench-wall 84 is formed to comprise anupper portion of second trench sidewall 30 a. Such may occur whereconductive material 34 a/35 a is etched selectively relative todamascene material 24 a such that negligible etching of sidewalls 28 aand 30 a occurs above conductive material 34 a/35 a. Alternately ifdamascene material 24 a is etched laterally during or after etch ofconductive material 34 a/35 a, the first trench-wall and the secondtrench-wall may be laterally cut-back (not shown) such that the trencheswiden above conductive material 34 a/35 a.

Referring to FIGS. 20 and 21, a first etch mask 86 has been formedagainst first trench-wall 82 and a second etch mask 88 has been formedagainst second trench-wall 84. In one embodiment, such may be formed bydepositing a spacer-forming layer to less than fill remaining volume oftrenches 25 a after the act of recessing depicted by FIG. 19.Thereafter, the spacer-forming layer may be anisotropically etched toform the depicted first and second etch masks to respectively comprise asidewall spacer received against the first and second trench-walls,respectively. Accordingly, deposited thickness of the spacer-forminglayer may be used to largely determine the lateral dimensions of thefirst and second etch masks. In one embodiment, such anisotropic etchingmay be conducted without any mask being received over the spacer-forminglayer, for example to avoid adding a mask step as was depicted by way ofexample in FIGS. 11 and 12 of the first-described embodiment.Alternately, a lithographic masking step may be conducted to form thefirst and second etch masks. Regardless, first and second etch masks 86,88 may alternately be formed, by way of example, by thermal growthlaterally inward from first trench-wall 82 and from second trench-wall84.

First and second etch masks 86, 88 may be formed of insulative,conductive, and/or semiconductive material, for example depending uponwhether some or all of the material from which the first and second etchmasks are formed is to remain as part of the finished integratedcircuitry construction. One example comprises an oxide, such as silicondioxide, deposited by atomic layer deposition. In one embodiment, theetch rate of the material of the first and second etch masks in a givenchemistry is higher than the etch rate of damascene material 24 a.

FIG. 20 depicts one embodiment wherein the first and second etch masksare formed to comprise an interconnected ring within each trench 25 a.The lower terminuses of trenches 25 a will, for example, comprise mirrorimages of that depicted in FIG. 20 whereby the material from which firstand second etch masks 86 and 88 are formed interconnects to form a ringwithin each trench 25 a. Pinching-off (not shown) may occur of thematerial from which the first and second etch masks are formed at thewidened ends of the depicted example trenches 25 a.

Referring to FIGS. 22 and 23, and using first etch mask 86 and secondetch mask 88 as masking, etching has been conducted through conductivematerial 34 a/35 a longitudinally between the first and second trenchsidewalls 28 a and 30 a, respectively. Such forms a longitudinal contourof second sidewall 58 of first conductive line 52 within each trench 25a and forms a longitudinal contour of second sidewall 58 of secondconductive line 56 within each trench 25 a.

FIGS. 22 and 23 show an embodiment wherein first conductive line 52 andsecond conductive line 56 as initially formed comprise an interconnectedring of conductive material, for example as being formed using aninterconnected ring of the first and second etch masks 86 and 88 as anetching mask. Such ring of conductive material may be broken in at leasttwo locations to separate first conductive line 52 from beingelectrically interconnected with second conductive line 56 within eachtrench. An example manner for doing so is described with reference toFIGS. 24 and 25.

In FIGS. 24 and 25, masking material 90 has been deposited as part ofsubstrate 10 a, and mask openings 92 have been formed there-through ator near the ends of the respective trenches. Corresponding mask openings92 (not shown) would be formed at the opposing ends relative to eachrespective trench 25 a. An example masking material 90 is photoresist.

Referring to FIG. 26, the interconnected portions of the material of thefirst and second etch masks 86, 88 are etched, followed by subsequentetching of conductive material 34 a/35 a. Masking material 90 (notshown) has been subsequently removed. Alternately, some or all of suchmight remain depending in part upon its composition. One or moresuitable etching chemistries may be selected by the artisan for etchingof the masking material of masks 86, 88 followed by conductive material34 a/35 a. One or a combination of dry and wet etching may be used. Inone embodiment, at least a majority of each of the first and second etchmasks remain as part of the finished integrated circuitry. For example,where the material of first and second etch masks 86 and 88 isinsulative, such may largely remain, for example in the embodimentdepicted by FIG. 26.

In one embodiment, a method of forming a pair of conductive lines in thefabrication of integrated circuitry includes formation of a trench intoa damascene material which is received over a substrate. Conductivematerial is deposited over the damascene material and to within thetrench to overfill the trench. The conductive material is removed backat least to the damascene material to leave at least some of theconductive material remaining in the trench. Longitudinal etching isconducted through the conductive material within the trench to formfirst and second conductive lines within the trench which are mirrorimages of one another in lateral cross section along at least a majorityof length of the first and second conductive lines. Processing as shownand described above are but some examples of such a method.

One embodiment of the invention encompasses a method of forming an arrayof conductive lines in the fabrication of integrated circuitry. Suchincludes formation of a plurality of elongated conductive lines over asubstrate. Processing may be conducted, for example, as shown anddescribed above. Alternately by way of example only, such plurality ofelongated conductive lines might be fabricated solely using subtractivepatterning and etching techniques, as well as using other techniqueswhether existing or yet-to-be developed. Combinations of differenttechniques may also be used.

First and second alternating regions of dielectric material are providedbetween the conductive lines laterally across the array. The firstregions comprise a singular void received within solid insulativematerial between two immediately adjacent of the conductive lines. Thesecond regions are at least in part characterized by an absence of anyvoid space within solid insulative material between two immediatelyadjacent conductive lines. By way of example only, the above-describedprocessings in production of the FIG. 17 array of conductive lines arebut examples. Such depicts example first regions 80 as beingcharacterized by a combination of dielectric material 70 and void space72 received between conductive lines 52 and 56. Conductive lines 52 and56 may or may not be mirror images of one another, and may otherwise bedifferent or the same as one another. First regions 80 alternate withsecond regions 82 that are characterized by an absence of any void spacewithin solid insulative material 17 received between the respectivepairs of conductive lines 52 and 56. Regardless, the first and secondregions may be fabricated at the same or different times. Theabove-described embodiment shows a method wherein first regions 80having a void 72 are formed after forming second regions 82 which do nothave any void space. Regardless, processing may otherwise be conductedas described above or otherwise.

Embodiments of the invention also encompass integrated circuitrycomprising an array of conductive lines and independent of method offabrication. In one embodiment, such circuitry and array includes aplurality of elongated conductive lines received over a substrate. Firstand second alternating regions of dielectric material are receivedbetween the conductive lines laterally across the array. The firstregions comprise a singular void received within solid insulativematerial between two immediately adjacent of the conductive lines. Thesecond regions are at least in part characterized by an absence of anyvoid space within solid insulative material between two immediatelyadjacent of the conductive lines. Again by way of example only, FIG. 17shows such example circuitry having an array of conductive lines.

In one embodiment, integrated circuitry comprising an array ofconductive lines includes a plurality of elongated conductive linesreceived over a substrate. The conductive lines are at least in partcharacterized by repeating pairs of immediately adjacent conductivelines which are mirror images of one another in lateral cross sectionalong at least a majority of length of the repeating pairs. Conductivelines 52 and 56 as shown and described above are but examples ofimmediately adjacent conductive lines which are mirror image of oneanother.

Dielectric material is received between the conductive lines over thesubstrate laterally across the array. Such may or may not comprise firstand second alternating regions received between the conductive lineslaterally across the array with and without a singular void as describedabove.

Further and regardless, the above described and depicted mirror imagelines 52 and 56 may advantageously provide greater conductivity due tobeing lined on only one side with material 34. For example, a layer 34may be provided to function as a diffusion barrier and/or adhesion layerrelative to underlying material. Such may be desired where, for example,material 35 deposited thereover is lacking in diffusion barrier and/oradhesion properties relative to underlying or surrounding material. Insuch instance(s), the diffusion barrier/adhesion material may be oflower electrical conductivity than the conductive material depositedthereover. Providing the depicted mirror image lines having only oneside largely composed of the lower conductive material may increaseoverall conductivity of the conductive lines being formed.

In compliance with the statute, the subject matter disclosed herein hasbeen described in language more or less specific as to structural andmethodical features. It is to be understood, however, that the claimsare not limited to the specific features shown and described, since themeans herein disclosed comprise example embodiments. The claims are thusto be afforded full scope as literally worded, and to be appropriatelyinterpreted in accordance with the doctrine of equivalents.

1. A method of forming a plurality of conductive lines in the fabrication of integrated circuitry, comprising: forming a trench into a damascene material received over a substrate, the trench having first and second opposing trench sidewalls, the first trench sidewall being longitudinally elongated to comprise a longitudinal contour of a first sidewall of one of the plurality of conductive lines being formed, the second trench sidewall being longitudinally elongated to comprise a longitudinal contour of a first sidewall of another of the plurality of conductive lines being formed; depositing conductive material to within the trench to span between the first and the second trench sidewalls; and etching through the conductive material longitudinally between the first and second trench sidewalls to form the longitudinal contour of a second sidewall of the one conductive line within the trench and to form the longitudinal contour of a second sidewall of the another conductive line within the trench.
 2. The method of claim 1 comprising forming no more than two conductive lines within the trench.
 3. The method of claim 1 wherein a minimum space between the longitudinal contours within each of the one and the another conducive lines is no greater than 20 nanometers.
 4. The method of claim 1 wherein the etching forms the one conductive line and the another conductive line to be of the same shape in lateral cross section along at least a majority of length of the one conductive line and the another conductive line.
 5. The method of claim 4 wherein the etching forms the one conductive line and the another conductive line to be mirror images of one another in lateral cross section along at least the majority of length of the one conductive line and the another conductive line.
 6. The method of claim 1 wherein the conductive material is deposited to overfill the trench, and further comprising planarizing the conductive material back at least to the damascene material prior to the etching through the conductive material.
 7. A method of forming a pair of conductive lines in the fabrication of integrated circuitry, comprising: forming a trench into a damascene material received over a substrate, the trench having first and second opposing trench sidewalls and a minimum width there-between which is at least about 3 W_(m) where W_(m) is the minimum width of the conductive lines being formed, the first trench sidewall being longitudinally elongated to comprise a longitudinal contour of a first sidewall of a first of the pair of conductive lines being formed, the second trench sidewall being longitudinally elongated to comprise a longitudinal contour of a first sidewall of a second of the pair of conductive lines being formed; depositing conductive material to within the trench to span between the first and second trench sidewalls; and etching through the conductive material longitudinally between the first and second trench sidewalls to form the longitudinal contour of a second sidewall of the first conductive line within the trench and to form the longitudinal contour of a second sidewall of the second conductive line within the trench.
 8. The method of claim 7 wherein the trench minimum width is about 3 W_(m).
 9. The method of claim 8 wherein the integrated circuitry is fabricated using photolithography and W_(m) is F, where F is the minimum photolithographic feature size with which the integrated circuitry is fabricated.
 10. The method of claim 8 wherein the integrated circuitry is fabricated using photolithography and W_(m) is less than F, where F is the minimum photolithographic feature size with which the integrated circuitry is fabricated.
 11. The method of claim 7 wherein the etching forms the first and second conductive lines to be of the same shape in lateral cross section along at least a majority of length of the first and second conductive lines.
 12. The method of claim 11 wherein the trench minimum width is about 1.5 P, where P is pitch of the first and second conductive lines.
 13. The method of claim 11 wherein the etching forms the first and second conductive lines to be mirror images of one another in lateral cross section along at least a majority of length of the first and second conductive lines.
 14. The method of claim 11 wherein the trench minimum width is about 3W_(m).
 15. The method of claim 14 wherein the trench minimum width is about 1.5 P, where P is pitch of the first and second conductive lines.
 16. The method of claim 7 wherein the etching forms a space within the trench between the first and second conductive lines, and further comprising filling the space with a dielectric material.
 17. The method of claim 16 wherein the dielectric material comprises a void between the first and second conductive lines.
 18. The method of claim 7 wherein the etching forms a space within the trench between the first and second conductive lines, the space being equal to about W_(m) in lateral cross section.
 19. The method of claim 7 wherein the conductive material within the trench comprises a conductive liner comprising a first composition and a conductive fill material comprising a different second composition received over the conductive liner.
 20. The method of claim 19 wherein the etching forms each of the first and second conductive lines to have the first sidewall of the first composition and a base layer of the first composition, the etching forming the second sidewall above the base layer of each of the first and second conductive lines to be of the second composition.
 21. The method of claim 19 wherein second composition is of higher electrical conductivity than the first composition.
 22. A method of forming a plurality of parallel conductive lines in the fabrication of integrated circuitry, comprising: forming a plurality of parallel oriented trenches into a damascene material received over a substrate, the trenches individually having first and second opposing trench sidewalls and a minimum width there-between which is at least about 3 W_(m) where W_(m) is the minimum width of a pair of conductive lines being formed within each trench, the first trench sidewall of each trench being longitudinally elongated to comprise a longitudinal contour of a first sidewall of a first of the pair of conductive lines being formed within each trench, the second trench sidewall being longitudinally elongated to comprise a longitudinal contour of a second sidewall of a second of the pair of conductive lines being formed within each trench; depositing conductive material to within each trench to span between the first and second trench sidewalls of each trench; and etching through the conductive material longitudinally between the first and second trench sidewalls to form the longitudinal contour of a second sidewall of the first conductive line within each trench and to form the longitudinal contour of a second sidewall of the second conductive line within each trench.
 23. The method of claim 22 wherein W_(m) is no greater than 20 nanometers.
 24. The method of claim 22 wherein the etching is conducted through openings between masking blocks, the masking blocks individually spanning between and partially masking respective immediately adjacent of two of the trenches.
 25. The method of claim 22 wherein the etching forms the first and second conductive lines to be mirror images of one another in lateral cross section along at least a majority of length of the first and second conductive lines.
 26. The method of claim 22 comprising forming the damascene material to comprise insulative material at least some of which remains a part of the finished integrated circuitry.
 27. The method of claim 22 comprising forming the damascene material to comprise at least one of semiconductive material and conductive material.
 28. A method of forming a pair of conductive lines in the fabrication of integrated circuitry, comprising: forming a trench into a damascene material received over a substrate, the trench having first and second opposing trench sidewalls which span an elevation of the damascene material, the first trench sidewall being longitudinally elongated to comprise a longitudinal contour of a first sidewall of a first of a pair of conductive lines being formed within the trench, the second trench sidewall being longitudinally elongated to comprise a longitudinal contour of a first sidewall of a second of the pair of conductive lines being formed within the trench; depositing conductive material to within the trench to span between the first and second trench sidewalls; recessing the conductive material within the trench and forming a first trench-wall and a second trench-wall over the recessed conductive material, the first trench-wall and the second trench-wall being received within said elevation of the damascene material; forming a first etch mask against the first trench-wall and a second etch mask against the second trench-wall; and using the first etch mask and the second etch mask as masking, etching through the conductive material longitudinally between the first and second trench sidewalls to form the longitudinal contour of a second sidewall of the first conductive line within the trench and to form the longitudinal contour of a second sidewall of the second conductive line within the trench. 29-38. (canceled)
 39. A method of forming a plurality of parallel conductive lines in the fabrication of integrated circuitry, comprising: forming a plurality of parallel oriented trenches into a damascene material received over a substrate, the trenches individually having first and second opposing trench sidewalls and a minimum width there-between which is at least about 3 W_(m) where W_(m) is the minimum width of a pair of conductive lines being formed within each trench, the first and second opposing trench sidewalls spanning an elevation of the damascene material, the first trench sidewall of each trench being longitudinally elongated to comprise a longitudinal contour of a first sidewall of a first of the pair of conductive lines being formed within each trench, the second trench sidewall being longitudinally elongated to comprise a longitudinal contour of a second sidewall of a second of the pair of conductive lines being formed within each trench; depositing conductive material to within each trench to span between the first and second trench sidewalls of each trench; recessing the conductive material within each trench and forming a first trench-wall and a second trench-wall over the recessed conductive material within each trench, the first trench-wall and the second trench-wall within each trench being received within said elevation of the damascene material; forming a first etch mask against the first trench-wall and a second etch mask against the second trench-wall within each trench; and using the first etch masks and the second etch masks as masking, etching through the conductive material longitudinally between the first and second trench sidewalls to form the longitudinal contour of a second sidewall of the first conductive line within each trench and to form the longitudinal contour of a second sidewall of the second conductive line within each trench. 40-44. (canceled)
 45. A method of forming a pair of conductive lines in the fabrication of integrated circuitry, comprising: forming a trench into a damascene material received over a substrate; depositing conductive material over the damascene material and to within the trench to overfill the trench; removing the conductive material back at least to the damascene material to leave at least some of the conductive material remaining in the trench; and longitudinally etching through the conductive material within the trench to form first and second conductive lines within the trench which are mirror images of one another in lateral cross section along at least a majority of length of the first and second conductive lines.
 46. A method of forming an array of conductive lines in the fabrication of integrated circuitry, comprising: forming a plurality of elongated conductive lines over a substrate; and providing first and second alternating regions of dielectric material between the conductive lines laterally across the array, the first regions comprising a singular void received within solid insulative material between two immediately adjacent of the conductive lines, the second regions being at least in part characterized by an absence of any void space within solid insulative material between two immediately adjacent conductive lines. 47-48. (canceled)
 49. Integrated circuitry comprising an array of conductive lines, comprising: a plurality of elongated conductive lines received over a substrate; and first and second alternating regions of dielectric material received between the conductive lines laterally across the array, the first regions comprising a singular void received within solid insulative material between two immediately adjacent of the conductive lines, the second regions being at least in part characterized by an absence of any void space within solid insulative material between two immediately adjacent of the conductive lines.
 50. Integrated circuitry comprising an array of conductive lines, comprising: a plurality of elongated conductive lines received over a substrate, the conductive lines being at least in part characterized by repeating pairs of immediately adjacent conductive lines which are mirror images of one another in lateral cross section along at least a majority of length of the repeating pairs; and dielectric material received between the conductive lines over the substrate laterally across the array. 51-52. (canceled) 